A so-called thermoelectric effect describes energy conversion from a thermal gradient to electrical energy, where a temperature difference (i.e. thermal gradient) between one or more conducting materials results in heat flow and the diffusion of charge carriers. Typically, the flow of charge carriers between two regions of differing temperatures can create a voltage difference that allows for energy harvesting.
Prior systems have focused on improving converter efficiency and migrating from mechanical to electrical start-up circuits. However, harvesting energy in natural environments such as in biomedical applications can be challenging due to limited (<2K) thermal gradients. Further, in biomedical implants and wearable electronics, it is typically difficult to achieve sufficient gradient from the harvesting interface and also include a highly-efficient power management system.